1. Field of the Invention
The present disclosure relates to a light emitting device and a method of manufacturing the light emitting device.
2. Description of the Related Art
A light emitting diodes (LEDs) is a semiconductor light emitting element produced from a metal compound such as gallium nitride (GaN). Combining such a semiconductor light emitting element and a fluorescent material, various light emitting devices to emit light of a while color, an incandescent lamp color, an orange color and so on have been developed. Those light emitting devices to emit a white light and so on can be obtained based on the principle of light-color mixing. As for the system to emit a white light, there are well-known systems such as a system which employs an ultraviolet-light emitting element and three types of fluorescent materials which emit lights of a red (R) color, green (G) color, and blue (B) color, respectively, and a system which employs a blue-light emitting element and a yellow-light emitting fluorescent material. Light emitting devices of the type which employ a blue-light emitting element and a fluorescent material to emit yellow light etc., are in demand in a wide range of fields such as general lighting, on-vehicle lighting, displays, backlights for liquid crystal devices. Of those, for the fluorescent materials used for a backlight of liquid crystal device, in order to reproduce a wide range of colors on a chromaticity diagram, high color purity is also demanded along with the light emitting efficiency. Particularly, the fluorescent materials used for backlights for liquid crystal devices are required to have compatibility in combination with a color filter, and for which, a fluorescent material with a narrow half width of the emission peak has been in demand.
Examples of known red fluorescent materials which have an excitation band in blue-color region and a narrow half width of the emission peak include fluoride fluorescent materials with compositions of:
K2AlF5:Mn4+, K3AlF6:Mn4+, K3GaF6:Mn4+, Zn2AlF7:Mn4+, KIn2F7:Mn4+, K2SiF6:Mn4+, K2TiF6:Mn4+, K3ZrF7:Mn4+, Ba0.65Zr0.35F2.70:Mn4+, BaTiF6:Mn4+, K2SnF6:Mn4+, Na2TiF6:Mn4+, Na2ZrF6:Mn4+, KRbTiF6:Mn4+, and K2Si0.5Ge0.5F6:Mn4+ (for example, see JP 2009-528429A).
Generally, in light emitting devices, in order to protect the light emitting element, the light emitting element together with the bonded wires and other electrically conductive members is sealed with a sealing material which contains a fluorescent material.